I assume the update was done via the PC software, right ?
It seems that your DS708 cannot see or read the SD card.

Try to remove the card and insert while this image is on the screen.
If that works you have a format issue with the card (format in a digital camera in this case)

I would try another SD. Format in a digital camera, insert into the PC and install software and cars on in.
Eject from PC (right click on the drive icon) and insert into the DS708.

Can be a format issue, file system issue.
In the worst case it can be also the SD slot in the DS708, But I have never seen a report on this.